Y'know, I can't believe it's only a month and a half away. Feels like last E3 was just a month ago. I only count Nintendo's press conference and anything associated with it as E3 announcements, and no one else, but here are some concrete and some not-so-concrete things that I would bet money on, even though no one would take me up on these bets:
Skyward Sword will get a release window (other than 2011) and another trailer, if not an actual release date.
Wii Play Motion and The Legend of Zelda: Ocarina of Time 3D will have trailers.
Some new Wii game will be announced to satisfy owners for this "holiday season". Maybe a new IP since we've had so many good revivals and stuff last year, but you never know.
3DS and Wii sales figures will be touched on, no doubt.
A few 3DS games will get trailers, specifically, Star Fox, MK 3DS, Kid Icarus, and/or any of the other possible choices.
The Wii successor rumors may be spoken about. I'm speculating a Wii setup, with a codename and revolutionary features this year, a real name next year, and a release after that. I truly want to know how rumors like these spread so quickly. Trusted sources. Pah.
OH. Of course. Mario 3DS will certainly get a trailer.
I'll add more if I think of more.